1. Field of Invention
The present invention relates to processes of synthesizing aromatic amine-based benzoxazine resin. More particularly, the present invention relates to processes of synthesizing benzoxazines by employing multifunctional aromatic amines as a material.
2. Description of Related Art
Phenol formalde resin is a common thermosetting resin, which made by polycondensating the phenol monomer with aldehyde monomer. Benzoxazine is one of the phenol formalde resins, and the particularity of the benzoxazine monomer is the ring structure could be opened and the cured by heating. In compared with the conventional phenol formaldehyde resins, the benzoxazine is uninflammable and provides higher glass transition temperature (Tg), higher modulus, lower moisture absorption, greater electric properties, and higher char yield. Besides, the benzoxazine harden process is strong acid catalyst unneeded, no by-product produced and none of volume changed in progress.
The most commonly used benzoxazine is B-m and B-a. The synthesis of the B-m is reacting the diphenol A with formaldehyde and methylamine. The synthesis of the B-a is reacting the diphenol with formaldehyde and aniline. The routes of synthesizing the B-m and B-a resin are presented as follow:
